Introduction of tire pattern knowledge
The tire pattern is the “groove” on the tire. There is a lot of knowledge here. What about the tire pattern model?
The tire size is printed on the tire wall, there are two kinds of representation methods, such as 34*7 or 7.50-20. The former is a high-pressure tire, the latter is a low-pressure tire. There are also many signs, such as D for light cars, F for medium cars, G for standard cars, H, L, J for large luxury and high-performance cars. If an R is printed on the tire wall, such as 175R13, it means that the tire is a radial tire, with a width and length of 175mm (6.9 inches), and it is mounted on the wheel with a diameter of 13 inches (330mm) on the wheel. The word RADIAL is also usually engraved.
The international standard tire code expresses the percentage of section height and flatness ratio in millimeters. Add the following: tire type code, rim diameter (inch), load index (permitted load quality code), allowable speed code. For example: in 175/70R 14 77H, 175 represents the tire width is 175mm, 70 represents the flatness ratio of the tire section is 70%, that is, the section height is 70% of the width, R represents the radial tire, the rim diameter is 14 inches, the load index is 77, The allowable speed is class H.
The types of patterned tires are roughly divided into five categories:
1. Vertical and horizontal pattern
Advantages: It absorbs the advantages of good drainage performance and low noise of the longitudinal pattern, while taking into account the strength of the dynamic performance of the transverse pattern. It has better driving force and braking performance than the pure longitudinal pattern. Therefore, this type of pattern tire has strong adaptability and a wide range of applications. It is suitable for different hard roads and roads with poor road conditions. It is also suitable for cars and trucks. Therefore, the pattern of both vertical and horizontal patterns has become a tire Mainstream pattern.
Disadvantages: Abnormal wear and tear will occur.
2. Vertical pattern
Advantages: This pattern has excellent handling stability, small rotation resistance, and is not easy to slide laterally. Generally applicable to roads with better road conditions, such as highways or urban roads. The rolling resistance during driving is small, so the friction force with the ground is small, which has good driving direction and is suitable for high-speed driving. And the longitudinal tire drainage performance is excellent, it is not easy to slip on wet roads, and the noise during driving is also small.
Disadvantages: The braking performance of the longitudinal pattern tires is relatively weak, and the driving force is not as good as the tires of other patterns. It is not suitable for roads with poor conditions such as sand roads.
3. Off-road pattern
Advantages: The off-road pattern is specially designed to adapt to dry, wet, rugged mountain roads and muddy and sandy roads. This pattern tire is like a pentathlon athlete. It has several specialties and can be used in a variety of harsh environments and climates. Therefore, it is the best tire for young people or Jeep and other off-road vehicles. Cross-country patterns are divided into two types: directional patterns and directional patterns, of which directional patterns are directional when used. Off-road pattern tires are suitable for use on rough roads, soft dirt roads and no-road areas.
Disadvantages: Because the contact pressure of the pattern is large and the rolling resistance is large, it is not suitable for long-term driving on a good hard road. Otherwise, tire wear will increase, fuel consumption will increase, and vehicle vibration will be more severe.
4. Horizontal pattern
Advantages: Because the pattern adopts a horizontal design, the contact area between the tire and the ground is increased. Both the braking force and the driving force are excellent, which makes up for the shortcomings of the longitudinal pattern tire. It is suitable for the bad countryside and construction sites. Traffic conditions.
Disadvantages: Poor drainage and poor tire heat dissipation. In addition, the lateral tire increases noise while increasing the ground contact area. In terms of vehicle handling flexibility, it is clearly inferior to longitudinally patterned tires.
5. Mud and snow pattern
Advantages: The tire pattern is arranged in blocks. When the vehicle is driving on snow or muddy ground, the pattern is deeply embedded in the snow or muddy soil, and the vehicle generates driving force. Therefore, the block pattern has the best driving force and braking performance among the four pattern types. However, when using this type of tire, be sure to remove the studs on the tread, otherwise, it will damage the road surface.
Disadvantages: The cost of block pattern tires is relatively high, and this pattern is generally not used for special road conditions. Seasonality is too heavy, tires used in snow, can only be used in winter, and it takes a lot of trouble to save.
The role of tire pattern:
In short, the main function of the tire pattern is to increase the friction between the tread and the road surface to prevent the wheels from slipping, which is exactly the same as the sole pattern. The tire pattern improves the elasticity of the tread ground contact. Under the action of tangential forces (such as driving force, braking force and lateral force) between the tread and the road surface, the block can produce large tangential elastic deformation. When the tangential force increases, the tangential deformation increases accordingly, and the “friction effect” of the contact surface also increases, thereby suppressing the tendency of the tread to slip or slip. This largely eliminates the disadvantages of pattern-free (light tread) tires that are easy to slip, making the car performance related to the friction performance between the tire and the road surface-dynamic, braking, steering maneuverability and driving safety There is a reliable guarantee for normal play.
Studies have shown that the factors that produce the friction between the tread and the road surface also include the adhesion between the two surfaces, the molecular attraction effect, and the micro-cutting effect of the road surface convexity on the tread, but the main role is still the block Elastic deformation.